Help please!!

Hello Everyone,
Last year I planted a small greengage tree. It was doing very well this spring and had lots of small fruits on it. Unfortunately the leaves look like they have some sort of disease and the fruits are not getting any bigger. Please could someone suggest what might be wrong and if there is anything I can do to save it?
Many thanks.

 

Hi,
I have watered it but I haven't fed it at all. To be honest, I wasn't aware that I should be feeding it, and I must admit I wouldn't know what to feed it with. (I wish I knew more about gardening).
I have sprayed it with Bayer Fungus Fighter but it still looks really poorly. I have an established Victoria Plum tree that is looking a bit the same. I would be grateful if you could suggest a feed that I could try.
Thank you very much for any suggestion you could give.

 

Btw - I did prepare the hole with compost as instructed by the plant nursery that I got it from.

 

I didn't realise they needed that much water!! I use a full watering can every other day - so obviously that's not enough!
Thank you for the advice, I will get the feed that you suggest and hope that they will recover.
Do you think the fruits will be edible this year or are they too badly damaged?